减少 golang 二进制文件大小操作

$ go version
go version go1.11.2 linux/amd64

$ gcc --version
gcc (Ubuntu 5.4.0-6ubuntu1~16.04.10) 5.4.0 20160609

package main
import "fmt"
func main() {
 fmt.Println("hello world")
}

#include <stdio.h>
int main() {
 printf("hello world\n");
 return 0;
}

$ go build -o hello hello.go
$ go build -ldflags "-s -w" -o hello2 hello.go
$ gcc hello.c

$ ls -l
-rwxrwxr-x 1 zengxl zengxl 1902849 11月 27 15:40 hello
-rwxrwxr-x 1 zengxl zengxl 1353824 11月 27 15:43 hello2
-rwxrwxr-x 1 zengxl zengxl 8600 11月 27 15:44 a.out

$ go tool link -h

usage: link [options] main.o
-s disable symbol table  # 去掉符号表
-w disable DWARF generation # 去掉调试信息

$ readelf -h a.out 
ELF 头：
 Magic： 7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00 
 类别:        ELF64
 数据:        2 补码，小端序 (little endian)
 版本:        1 (current)
 OS/ABI:       UNIX - System V
 ABI 版本:       0
 类型:        EXEC (可执行文件)
 系统架构:       Advanced Micro Devices X86-64
 版本:        0x1
 入口点地址：    0x400430
 程序头起点：   64 (bytes into file)
 Start of section headers:   6616 (bytes into file)
 标志：    0x0
 本头的大小：  64 (字节)
 程序头大小：  56 (字节)
 Number of program headers:   9
 节头大小：   64 (字节)
 节头数量：   31
 字符串表索引节头： 28

$ readelf -d a.out 

Dynamic section at offset 0xe28 contains 24 entries:
 标记  类型       名称/值
 0x0000000000000001 (NEEDED)    共享库：[libc.so.6]
 0x000000000000000c (INIT)    0x4003c8
 0x000000000000000d (FINI)    0x4005b4
 0x0000000000000019 (INIT_ARRAY)   0x600e10
 0x000000000000001b (INIT_ARRAYSZ)  8 (bytes)
 0x000000000000001a (FINI_ARRAY)   0x600e18
 0x000000000000001c (FINI_ARRAYSZ)  8 (bytes)
 0x000000006ffffef5 (GNU_HASH)   0x400298
 0x0000000000000005 (STRTAB)    0x400318
 0x0000000000000006 (SYMTAB)    0x4002b8
 0x000000000000000a (STRSZ)    61 (bytes)
 0x000000000000000b (SYMENT)    24 (bytes)
 0x0000000000000015 (DEBUG)    0x0
 0x0000000000000003 (PLTGOT)    0x601000
 0x0000000000000002 (PLTRELSZ)   48 (bytes)
 0x0000000000000014 (PLTREL)    RELA
 0x0000000000000017 (JMPREL)    0x400398
 0x0000000000000007 (RELA)    0x400380
 0x0000000000000008 (RELASZ)    24 (bytes)
 0x0000000000000009 (RELAENT)   24 (bytes)
 0x000000006ffffffe (VERNEED)   0x400360
 0x000000006fffffff (VERNEEDNUM)   1
 0x000000006ffffff0 (VERSYM)    0x400356
 0x0000000000000000 (NULL)    0x0

$ readelf -h hello
ELF 头：
 Magic： 7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00 
 类别:        ELF64
 数据:        2 补码，小端序 (little endian)
 版本:        1 (current)
 OS/ABI:       UNIX - System V
 ABI 版本:       0
 类型:        EXEC (可执行文件)
 系统架构:       Advanced Micro Devices X86-64
 版本:        0x1
 入口点地址：    0x451fa0
 程序头起点：   64 (bytes into file)
 Start of section headers:   456 (bytes into file)
 标志：    0x0
 本头的大小：  64 (字节)
 程序头大小：  56 (字节)
 Number of program headers:   7
 节头大小：   64 (字节)
 节头数量：   13
 字符串表索引节头： 3

Commands:
 -1  compress faster     -9 compress better
 -d  decompress      -l list compressed file
 -t  test compressed file    -V display version number
 -h  give more help     -L display software license
Options:
 -q  be quiet       -v be verbose
 -oFILE write output to 'FILE'
 -f  force compression of suspicious files
 -k  keep backup files
file.. executables to (de)compress

Compression tuning options:
 --brute    try all available compression methods & filters [slow]
 --ultra-brute  try even more compression variants [very slow]

$ go build -o hello hello.go
$ go build -ldflags "-s -w" -o hello-strip hello.go
$ upx --brute hello

$ ll -h
-rwxr-xr-x 1 aland aland 1.9M Dec 6 13:06 hello
-rwxr-xr-x 1 aland aland 809K Dec 6 13:07 hello-upx
-rwxr-xr-x 1 aland aland 1.3M Dec 6 13:06 hello-strip